FIELD OF THE INVENTION
This invention relates to extension of pipe beneath a barrier such as a road, railroad, track, pipeline or the like when trenching is not feasible and more particularly, to a pipe pulling and pushing apparatus and method of operation. In a preferred embodiment the pipe pulling and pushing apparatus includes a spring-loaded wedge having a housing fitted with an internal coil spring intermittently engaging sliding, articulating wedge segments collectively provided with a bore for receiving the rod or pipe to be deployed and having teeth for selectively engaging and releasing the rod or pipe responsive to operation of a driving apparatus which receives the spring-loaded wedge. The driving apparatus is typically hydraulically operated to incrementally advance the rod or pipe with the spring-loaded wedge through the terrain beneath the barrier responsive to engagement and release of the wedge segments with the rod or pipe inside the spring-loaded wedge housing.
One of the problems realized in the laying of pipelines and piping of relatively small diameter is that of access under barriers such as highways, railroad tracks, existing pipelines and the like, where trenching is not feasible or practical. Various apparatus have been designed to effect extension of pipe or rods through such terrain beneath these barriers. Typical of these devices is the "Pipe Puller" detailed in U.S. Pat. No. 2,939,739, dated Jun. 7, 1960, to Grunsky. The Grunsky pipe puller is designed to engage the interior surface of a pipe and exert a pulling force on the pipe to pull the engaged pipe in the direction of the applied force. U.S. Pat. No. 3,787,950, dated Jan. 29, 1974, to Bagby, details an "Apparatus For Reclaiming Collet Hose Fittings". Collet-type hose fittings have malleable fingers radially clasped to secure the skived end of a hydraulic hose telescoped on its stem for securing to a mandrel having a coaxial plunger. U.S. Pat. No. 4,030,183, dated Jun. 21, 1977, to R. L. Smola, details a "Tool Assembly For Mounting And Removing Overhung Rolls. The tool assembly is used for mounting and removing work rolls on the end sections of roll shafts and is hydraulically actuated, with a piston removably attached to the roll shaft of the work roll and a cylinder. Operation of the piston within the cylinder mounts or removes the work roll. U.S. Pat. No. 5,112,070, dated May 12, 1992, to Kevin C. Hahn, details a "Dual Wheel Puller/Dolly". The pulley/dolly operates by an internal coil spring to facilitate removal of a wheel bearing from a wheel hub. U.S. Pat. No. 4,571,802, dated Feb. 25, 1986, to G. L. Calhoun, et al, details a "Double Grip, Relative Motion Tube Puller". The tube puller includes upper and lower gripping mechanisms for gripping the section of a tube surrounded by a tube sheet. The two gripping mechanisms are mechanically linked by an extendible connecting assembly which includes an outer sleeve where the lower gripping apparatus is located, and amid the sleeve where the upper gripping apparatus is positioned. The gripping apparatus coact to withdraw a tube from a tube sheet. U.S. Pat. No. 3,094,312, dated Jun. 18, 1963, to R. J. Woolgar, details a "Power Assisted Feed For A Kelly Bar". The apparatus includes a rotatable member having a central opening for the axial passage of a generally vertical kelly bar, at least two gripping members associated with a rotatable member and symmetrically disposed about the central opening and adapted to cooperate in releasably gripping the sides of the kelly bar. Further included is a thrust device for applying axial thrust to the rotatable member, such that downward thrust can be transmitted to the kelly bar. U.S. Pat. No. 2,889,135, dated Jun. 2, 1959, to W. Tennyck, details a "Pipe Pushing Machine". The machine includes a base frame work which mounts a reciprocating carriage having pipe clamping jaws. An operating component is connected to the carriage for reciprocating the carriage with respect to the base frame and manipulation of the operating component when a rod positioned in the lugs forces the rod through the ground.
It is an object of this invention to provide a new and improved rod and pipe pulling and pushing apparatus for pulling or pushing a rod or pipe through the terrain beneath a barrier.
Another object of the invention is to provide a new and improved rod or pipe pulling and pushing apparatus which is characterized by a spring-loaded wedge device that may be positioned in a driving apparatus to sequentially and incrementally pull or push the rod or pipe through the terrain beneath a barrier responsive to operation of the driving apparatus.
Still another object of the invention is to provide a rod or pipe pulling and pushing apparatus, a first element of which includes a spring-loaded wedge having a housing and a movable wedge defined by articulating wedge segments intermittently engaging a coil spring in the housing. A pipe or rod to be forced through the terrain beneath a barrier is extended through the wedge and the spring after the spring-loaded wedge is positioned in a driving apparatus, such that the rod or pipe may be incrementally and sequentially pulled or pushed through the terrain beneath the barrier by intermittent engagement and release of the rod or pipe by the wedge responsive to sliding movement of the wedge segments in the housing and operation of the driving apparatus.
Another object of the invention is to provide a spring-loaded wedge for use with a driving apparatus and a method for using the spring-loaded wedge for incrementally pushing or pulling a rod or pipe through the terrain beneath a barrier, which method includes the steps of positioning the spring-loaded wedge device for receiving the rod or pipe, placing the spring-loaded wedge device in the driving apparatus and operating the driving apparatus to successively engage and release internal, sliding wedge segments with the rod or pipe responsive to operation of the driving apparatus.